/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef LIBZIPARCHIVE_ZIPARCHIVE_PRIVATE_H_
#define LIBZIPARCHIVE_ZIPARCHIVE_PRIVATE_H_

#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>

#include <memory>
#include <vector>

#include <utils/FileMap.h>
#include <ziparchive/zip_archive.h>
#include "android-base/macros.h"

static const char* kErrorMessages[] = {
        "Success",
        "Iteration ended",
        "Zlib error",
        "Invalid file",
        "Invalid handle",
        "Duplicate entries in archive",
        "Empty archive",
        "Entry not found",
        "Invalid offset",
        "Inconsistent information",
        "Invalid entry name",
        "I/O error",
        "File mapping failed",
};

enum ErrorCodes : int32_t {
    kIterationEnd = -1,

    // We encountered a Zlib error when inflating a stream from this file.
    // Usually indicates file corruption.
    kZlibError = -2,

    // The input file cannot be processed as a zip archive. Usually because
    // it's too small, too large or does not have a valid signature.
    kInvalidFile = -3,

    // An invalid iteration / ziparchive handle was passed in as an input
    // argument.
    kInvalidHandle = -4,

    // The zip archive contained two (or possibly more) entries with the same
    // name.
    kDuplicateEntry = -5,

    // The zip archive contains no entries.
    kEmptyArchive = -6,

    // The specified entry was not found in the archive.
    kEntryNotFound = -7,

    // The zip archive contained an invalid local file header pointer.
    kInvalidOffset = -8,

    // The zip archive contained inconsistent entry information. This could
    // be because the central directory & local file header did not agree, or
    // if the actual uncompressed length or crc32 do not match their declared
    // values.
    kInconsistentInformation = -9,

    // An invalid entry name was encountered.
    kInvalidEntryName = -10,

    // An I/O related system call (read, lseek, ftruncate, map) failed.
    kIoError = -11,

    // We were not able to mmap the central directory or entry contents.
    kMmapFailed = -12,

    kLastErrorCode = kMmapFailed,
};

class MappedZipFile {
public:
    explicit MappedZipFile(const int fd)
            : has_fd_(true), fd_(fd), base_ptr_(nullptr), data_length_(0) {}

    explicit MappedZipFile(void* address, size_t length)
            : has_fd_(false), fd_(-1), base_ptr_(address), data_length_(static_cast<off64_t>(length)) {}

    bool HasFd() const { return has_fd_; }

    int GetFileDescriptor() const;

    void* GetBasePtr() const;

    off64_t GetFileLength() const;

    bool ReadAtOffset(uint8_t* buf, size_t len, off64_t off) const;

private:
    // If has_fd_ is true, fd is valid and we'll read contents of a zip archive
    // from the file. Otherwise, we're opening the archive from a memory mapped
    // file. In that case, base_ptr_ points to the start of the memory region and
    // data_length_ defines the file length.
    const bool has_fd_;

    const int fd_;

    void* const base_ptr_;
    const off64_t data_length_;
};

class CentralDirectory {
public:
    CentralDirectory(void) : base_ptr_(nullptr), length_(0) {}

    const uint8_t* GetBasePtr() const { return base_ptr_; }

    size_t GetMapLength() const { return length_; }

    void Initialize(void* map_base_ptr, off64_t cd_start_offset, size_t cd_size);

private:
    const uint8_t* base_ptr_;
    size_t length_;
};

struct ZipArchive {
    // open Zip archive
    mutable MappedZipFile mapped_zip;
    const bool close_file;

    // mapped central directory area
    off64_t directory_offset;
    CentralDirectory central_directory;
    std::unique_ptr<android::FileMap> directory_map;

    // number of entries in the Zip archive
    uint16_t num_entries;

    // We know how many entries are in the Zip archive, so we can have a
    // fixed-size hash table. We define a load factor of 0.75 and over
    // allocate so the maximum number entries can never be higher than
    // ((4 * UINT16_MAX) / 3 + 1) which can safely fit into a uint32_t.
    uint32_t hash_table_size;
    ZipString* hash_table;

    ZipArchive(const int fd, bool assume_ownership)
            : mapped_zip(fd),
              close_file(assume_ownership),
              directory_offset(0),
              central_directory(),
              directory_map(new android::FileMap()),
              num_entries(0),
              hash_table_size(0),
              hash_table(nullptr) {}

    ZipArchive(void* address, size_t length)
            : mapped_zip(address, length),
              close_file(false),
              directory_offset(0),
              central_directory(),
              directory_map(new android::FileMap()),
              num_entries(0),
              hash_table_size(0),
              hash_table(nullptr) {}

    ~ZipArchive() {
        if (close_file && mapped_zip.GetFileDescriptor() >= 0) {
            close(mapped_zip.GetFileDescriptor());
        }

        free(hash_table);
    }

    bool InitializeCentralDirectory(const char* debug_file_name, off64_t cd_start_offset,
                                    size_t cd_size);
};

#endif  // LIBZIPARCHIVE_ZIPARCHIVE_PRIVATE_H_